Indwelling device-related infections constitute a major cause of morbidity and mortality in hospitalized patients and add considerably to medical cost. Microbial biofilms tend to readily develop on all types of devices: urinary, endotracheal, intravenous and other types of catheters and implants inserted into more than 25% of patients during hospitalization. A variety of methods have been used to combat surface colonization of biomedical implants by bacteria and other microorganisms as well as the resulting biofilm formed. Previous methods have included varying the fundamental biomaterial used in the devices, applying hydrophilic, hydrophobic or bioactive coatings or creating porous or gel surfaces on the devices that contain bioactive agents. Antimicrobial agents, such as antibiotics and polyclonal antibodies integrated into porous biomaterials have been shown to actively prevent microbial adhesion at the implant site. However, the effectiveness of such local-release therapies is often compromised by the increasing resistance of bacteria to antibiotic therapy and the specificity associated with antibodies. Mechanical approaches to preventing biofilm formation have utilized ultrasonic energy, yet the focus has thus far been on increasing biofilm sensitivity to antibiotics. Ultrasound combinations with antibiotics were found effective only in reducing E. coli biofilm burden in animal models, falling short of providing a comprehensive solution to the biofilm problem.
In addition, it is technically difficult to power such treatment systems, particularly for devices which are implanted in the body, and also to adequately spread the treatment over various shapes and configurations of devices.